During this week's Super Bowl, an ad for yoghurt made by Dannon in the US has featured music sounding very similar in feel and melody to Zebra.

Was this a case of unauthorised use of the John Butler Trio track? No, it is clearly a different recording. Is the music similar between the two? Yes.

Now here's the kicker. Is this an infringement of copyright?

Well...? Who's to say. Really - who's to say? Who will make a public, legal ruling that there has been an infringement of copyright in this case? I strongly believe NO ONE will. And I will stand corrected and surprised if this uproar amounts to anything more than an undisclosed out of court settlement between the two parties.

Why? Simple. Because music is very complex and questions of similarity are incredibly hard to quantify. The instruments used, pitch, speed, melody, number and placement of rests, time signatures, additional layers added or subtracted all have an impact on how "similar" one track may seem to another - and it is all subjective. But what is the threshold beyond which a track could be seen to infringe upon another?